The microstructural changes in the machined surface layer of Ni-based super alloys essentially determine the final performance of the structural components of aerospace engines in which these alloys are used.In this w...The microstructural changes in the machined surface layer of Ni-based super alloys essentially determine the final performance of the structural components of aerospace engines in which these alloys are used.In this work,multiscale metallurgical observations using scanning electron microscopy,electron-backscatter diffraction microscopy,and transmission electron microscopy were conducted to quantitatively characterize the microstructure of the machined subsurface.Next,to elucidate the factors that affect the formation of the refinement microstructure,the distributions of the deformation parameters(strain,strain rate,and temperature) in the machined subsurface were analyzed.A dislocation–twin interaction dynamic recrystallization mechanism for grain refinement during machining of Inconel 718 is proposed.Furthermore,microhardness evolution induced by grain refinement in the machined surface is evaluated.The results suggest that the gradient microstructure and the work hardening can be optimized by controlling the cutting parameters during turning of Inconel 718.展开更多
目的探究下背痛(low back pain,LBP)发生的主要危险因素,为今后LBP防治及干预提供理论依据。方法2021年12月—2022年12月,以整群抽样法选择在全国11家医院就诊的LBP患者为病例组(n=394),选择在同一医院其他疾病患者或其他健康人群作为...目的探究下背痛(low back pain,LBP)发生的主要危险因素,为今后LBP防治及干预提供理论依据。方法2021年12月—2022年12月,以整群抽样法选择在全国11家医院就诊的LBP患者为病例组(n=394),选择在同一医院其他疾病患者或其他健康人群作为对照组(n=413)。通过电子问卷收集研究对象一般个人情况、职业因素、生活及社会心理因素等数据。运用R语言统计软件分析数据,利用多因素logistic回归分析探究LBP的影响因素,并采用相乘及相加交互作用模型对职业及生活因素进行交互作用分析。结果病例组人员平均年龄为(47.65±11.24)岁;对照组平均年龄为(46.54±11.31)岁。多因素logistic回归分析结果显示:相对于体重过轻、不从事重复性工作、通勤时不使用手机、对薪酬不满意者,体重超重和肥胖、从事重复性工作、通勤时使用手机和对薪酬满意者发生LBP的风险升高至1.759~3.713倍(P<0.05);相对于文化程度为小学或以下者、行政管理人员,文化程度较高者及专业技术人员、办事人员、军人和操作设备相关人员发生LBP的风险降低至0.144~0.571倍(P<0.05)。交互作用分析结果显示,重复性工作和通勤时使用手机之间存在相乘交互作用(OR=3.743,95%CI:2.181~6.424)。结论LBP的发生与多个个体因素、职业因素和生活因素相关,且工作和生活因素对LBP的发生可能存在叠加效应。用人单位应采取合理的预防措施降低LBP的发生风险,保障劳动者职业健康。展开更多
Augmented reality superimposes digital information onto objects in the physical world and enables multi-user collaboration.Despite that previous proxemic interaction research has explored many applications of user-obj...Augmented reality superimposes digital information onto objects in the physical world and enables multi-user collaboration.Despite that previous proxemic interaction research has explored many applications of user-object distance and user-user distance in an augmented reality context,respectively,and combining both types of distance can improve the efficiency of users’perception and interaction with task objects and collaborators by providing userswith insight into spatial relations of user-task object and user-user,less is concerned about howthe two types of distances can be simultaneously adopted to assist collaboration tasks acrossmulti-users.To fulfill the gap,we present UOUU,the user-object distance and user-user distance combined method for dynamically assigning tasks across users.We conducted empirical studies to investigate how the method affected user collaboration tasks in terms of collaboration occurrence and overall task efficiency.The results show that the method significantly improves the speed and accuracy of the collaboration tasks as well as the frequencies of collaboration occurrences.The study also confirms the method’s effects on stimulating collaboration activities,as the UOUU method has effectively reduced the participants’perceived workload and the overall moving distances during the tasks.Implications for generalising the use of the method are discussed.展开更多
One crucial measure of strengthening and advancing the Party's work on ethnic affairs in the new era is to promote interaction,communication and integration of various ethnic groups,so as to enhance commonality.En...One crucial measure of strengthening and advancing the Party's work on ethnic affairs in the new era is to promote interaction,communication and integration of various ethnic groups,so as to enhance commonality.Entering the new era,Inner Mongolia,Guangxi and Ningxia have achieved remarkable results in encouraging interaction,communication and integration of various ethnic groups.By comparatively analyzing successes of the three autonomous regions through the perspective of promoting commonality,this article summarizes the following strategic revelations:1)we should comprehensively implement the Party's ethnic policies and ensure theactual implementation of mutual interaction,mutual communication and mutual integration of ethnic groups;2)we should proactively promote the substantial progress of the economy,so as to provide solid material foundation for mutual interaction,mutual communication and mutual integration of ethnic groups;3)we should facilitate activities that promote ethnic unity and progress,so that the promotion of interaction,communication and mutual integration of ethnic groups can be seen,be felt and gain actual outcomes;4)we should take measures that suit to local conditions and explore all-round embedding mechanisms in order to foster the ethos for mutual interaction,mutual communication and mutual integration of ethnic groups;5)we should make every effort to forge a strong sense of community for the Chinese nation and orient precisely to the cause of encouraging mutual interaction,mutual communication and mutual integration of ethnic groups.展开更多
基金financial support from the National Natural Science Foundation of China (No.51425503)the Major Science and Technology Program of High-end CNC Machine Tools and Basic Manufacturing Equipment of China (No.2014ZX04012014)supported by a grant from the Taishan Scholar Foundation of Shandong province (No.TS20130922)
文摘The microstructural changes in the machined surface layer of Ni-based super alloys essentially determine the final performance of the structural components of aerospace engines in which these alloys are used.In this work,multiscale metallurgical observations using scanning electron microscopy,electron-backscatter diffraction microscopy,and transmission electron microscopy were conducted to quantitatively characterize the microstructure of the machined subsurface.Next,to elucidate the factors that affect the formation of the refinement microstructure,the distributions of the deformation parameters(strain,strain rate,and temperature) in the machined subsurface were analyzed.A dislocation–twin interaction dynamic recrystallization mechanism for grain refinement during machining of Inconel 718 is proposed.Furthermore,microhardness evolution induced by grain refinement in the machined surface is evaluated.The results suggest that the gradient microstructure and the work hardening can be optimized by controlling the cutting parameters during turning of Inconel 718.
文摘目的探究下背痛(low back pain,LBP)发生的主要危险因素,为今后LBP防治及干预提供理论依据。方法2021年12月—2022年12月,以整群抽样法选择在全国11家医院就诊的LBP患者为病例组(n=394),选择在同一医院其他疾病患者或其他健康人群作为对照组(n=413)。通过电子问卷收集研究对象一般个人情况、职业因素、生活及社会心理因素等数据。运用R语言统计软件分析数据,利用多因素logistic回归分析探究LBP的影响因素,并采用相乘及相加交互作用模型对职业及生活因素进行交互作用分析。结果病例组人员平均年龄为(47.65±11.24)岁;对照组平均年龄为(46.54±11.31)岁。多因素logistic回归分析结果显示:相对于体重过轻、不从事重复性工作、通勤时不使用手机、对薪酬不满意者,体重超重和肥胖、从事重复性工作、通勤时使用手机和对薪酬满意者发生LBP的风险升高至1.759~3.713倍(P<0.05);相对于文化程度为小学或以下者、行政管理人员,文化程度较高者及专业技术人员、办事人员、军人和操作设备相关人员发生LBP的风险降低至0.144~0.571倍(P<0.05)。交互作用分析结果显示,重复性工作和通勤时使用手机之间存在相乘交互作用(OR=3.743,95%CI:2.181~6.424)。结论LBP的发生与多个个体因素、职业因素和生活因素相关,且工作和生活因素对LBP的发生可能存在叠加效应。用人单位应采取合理的预防措施降低LBP的发生风险,保障劳动者职业健康。
基金supported by Zhejiang Provincial R&D Programme(Ref No.2021C03128).
文摘Augmented reality superimposes digital information onto objects in the physical world and enables multi-user collaboration.Despite that previous proxemic interaction research has explored many applications of user-object distance and user-user distance in an augmented reality context,respectively,and combining both types of distance can improve the efficiency of users’perception and interaction with task objects and collaborators by providing userswith insight into spatial relations of user-task object and user-user,less is concerned about howthe two types of distances can be simultaneously adopted to assist collaboration tasks acrossmulti-users.To fulfill the gap,we present UOUU,the user-object distance and user-user distance combined method for dynamically assigning tasks across users.We conducted empirical studies to investigate how the method affected user collaboration tasks in terms of collaboration occurrence and overall task efficiency.The results show that the method significantly improves the speed and accuracy of the collaboration tasks as well as the frequencies of collaboration occurrences.The study also confirms the method’s effects on stimulating collaboration activities,as the UOUU method has effectively reduced the participants’perceived workload and the overall moving distances during the tasks.Implications for generalising the use of the method are discussed.
文摘One crucial measure of strengthening and advancing the Party's work on ethnic affairs in the new era is to promote interaction,communication and integration of various ethnic groups,so as to enhance commonality.Entering the new era,Inner Mongolia,Guangxi and Ningxia have achieved remarkable results in encouraging interaction,communication and integration of various ethnic groups.By comparatively analyzing successes of the three autonomous regions through the perspective of promoting commonality,this article summarizes the following strategic revelations:1)we should comprehensively implement the Party's ethnic policies and ensure theactual implementation of mutual interaction,mutual communication and mutual integration of ethnic groups;2)we should proactively promote the substantial progress of the economy,so as to provide solid material foundation for mutual interaction,mutual communication and mutual integration of ethnic groups;3)we should facilitate activities that promote ethnic unity and progress,so that the promotion of interaction,communication and mutual integration of ethnic groups can be seen,be felt and gain actual outcomes;4)we should take measures that suit to local conditions and explore all-round embedding mechanisms in order to foster the ethos for mutual interaction,mutual communication and mutual integration of ethnic groups;5)we should make every effort to forge a strong sense of community for the Chinese nation and orient precisely to the cause of encouraging mutual interaction,mutual communication and mutual integration of ethnic groups.
